X-ray detector with heating layer on converter material

ABSTRACT

A counting X-ray detector includes, in a stacked array, a converter material for converting X-ray radiation into electric charges and an electrode. In an embodiment, the electrode is electrically conductively connected to the converter material. The electrode is designed to be at least partly transparent. In an embodiment, the electrode includes: an electrically conductive contact layer, an electrically conductive first intermediate layer, an electrically conductive high voltage layer, a second intermediate layer and an electrically conductive heating layer.

PRIORITY STATEMENT

The present application hereby claims priority under 35 U.S.C. §119 toGerman patent application number DE 102015225774.6 filed Dec. 17, 2015,the entire contents of which are hereby incorporated herein byreference.

FIELD

At least one embodiment of the invention generally relates to a countingX-ray detector, a medical device and/or a method for regulating thetemperature of a converter material in an X-ray detector.

BACKGROUND

In X-ray imaging, for example in computed tomography, angiography, orradiography, counting direct-converting X-ray detectors can be used. TheX-ray radiation or the photons can be converted into electric pulses byan appropriate sensor. CdTe, CZT, CdZnTeSe, CdTeSe, CdMnTe, InP, TlBr₂,HgI₂, GaAs or others can be used, for example, as a converter materialfor the sensor.

The energy of the incident ionizing radiation is directly converted intoelectrical charges, known as electron-hole pairs. A high voltage, forexample, for CdTe, CZT, CdZnTeSe, CdTeSe or CdMnTe in the region of −500to −2000V, is applied to the converter material between an electrodeserving as a cathode and a readout contact serving as an anode, in orderto separate the charges of the electron-hole pairs triggered in theconverter material. The high voltage is applied to the electrode via anexternal high voltage source by way of an electrically conductivecontact.

The sensor is generally connected in a planar manner in a stacked arraywith a readout and/or an evaluation unit, for example, to an integratedcircuit (an Application Specific Integrated Circuit, ASIC), via solderedconnections, electrically conductive adhesive, or other methods. Theelectric pulses are evaluated by an evaluation unit, an ASIC forexample. The stacked array comprising the sensor and the integratedcircuit is connected to a further substrate, for example a printedcircuit board, a ceramic substrate such as, for example, HTCC or LTCC,or others. The electrical connections for reading out from the readoutand/or the evaluation unit can be designed as through connections(through-silicon via, TSV) or wire bonds.

DE 10 2012 213 410 B3 discloses a direct-converting X-ray radiationdetector, which comprises at least one electrode mounted on asemiconductor. The at least one electrode and the semiconductor areelectrically conductively connected, the at least one electrode beingdesigned to be transparent and electrically conductive.

U.S. Pat. No. 8,093,535 B2 discloses a circuit incorporated in asemiconductor material in order to measure signals from the sensorassigned to the integrated circuit. In at least one embodiment, thecircuit comprises an active component, a temperature sensor, and acircuit to control the temperature of the semiconductor material. Theactive component is designed to process measuring signals produced bythe sensor. The active component is intended to be controlled by thecircuit in an activatable manner around the temperature, such that thetemperature of the semiconductor material is variable. The circuitfurther comprises at least one of a PI- and PID-regulator in order tocontrol the temperature.

US 2003/0168605 A1 discloses a radiation detector having at least onesemi-conductive connection, the semiconductive connection being designedto generate electron-hole pairs through the detection of radiation andthe semiconductive connection being wired in a photovoltaic mode ofoperation. The detector has means for operating and maintaining theconnection at an almost constant temperature.

DE 100 34 262 C1 discloses a semiconductor device, wherein an integratedcircuit runs dummy work cycles in order to generate heat if thetemperature of the semiconductor device drops below a lower limitingvalue.

DE 101 38 913 A1 discloses a detector module for X-ray computertomographs, wherein a sensor array comprising a plurality of sensorelements is mounted on the front of a printed circuit board. To increasethe accuracy of the detector, provision is made according to theinvention on the back of the printed circuit board, which faces awayfrom the sensor array, for at least one heating element to be providedto heat the sensor array and for an electronic control unit arranged inthe vicinity of the heating element to control the heating element.

SUMMARY

The inventors have identified a problem in that the availability ofindium for the production of transparent electrodes comprisingindium-containing TCO (Transparent Conductive Oxide) is limited and thatthe production costs in the TCO deposition process are relatively high.The inventors have further identified a problem in that the indirectheating of the converter material, using for example, heating elementsin the evaluation unit or using heating elements on the underside of theevaluation unit do not provide adequate accuracy of temperaturestabilization.

Embodiments of the invention include a counting X-ray detector, amedical device and a method for regulating the temperature of aconverter material in an X-ray detector which allow an illumination ofthe converter material, the application of a high voltage to theconverter material and optionally a regulation of the temperature of theconverter material from a radiation incidence side.

Embodiments of the invention is directed to a counting X-ray detector ofa first type, a counting X-ray detector of a next type, a medicaldevice, and a method for regulating the temperature of a convertermaterial of an X-ray detector.

At least one embodiment of the invention relates to a counting X-raydetector comprising, in a stacked array, a converter material forconverting X-ray radiation into electrical charges, and an electrode.The electrode is electrically conductively connected to the convertermaterial. The electrode is designed to be at least partly transparent.The electrode has the following layers: an electrically conductivecontact layer, an electrically conductive first intermediate layer, anelectrically conductive high voltage layer, a second intermediate layer,and an electrically conductive heating layer.

According to one embodiment of the invention, the electrode furthercomprises a first carrier protection layer and/or a second carrierprotection layer.

According to one embodiment of the invention, the electrode furthercomprises a first carrier protection layer arranged in the region of thehigh voltage layer and/or a second carrier protection layer arranged inthe region of the heating layer.

At least one embodiment of the invention further relates to a countingX-ray detector comprising, in a stacked array, a converter material forconverting X-ray radiation into electrical charges and a furtherelectrode. The further electrode is electrically connected to theconverter material. The further electrode is designed to be at leastpartly transparent. The further electrode comprises the followinglayers: an electrically conductive contact layer, an electricallyconductive first intermediate layer and an electrically conductive highvoltage layer, which is designed in the shape of a mesh. The countingX-ray detector can further comprise a first carrier protection layer.

At least one embodiment of the invention further relates to a medicaldevice comprising an X-ray detector according to at least one embodimentof the invention. The advantages of the X-ray detector according toembodiments of the invention that comprises the electrode can betransferred to the medical device according to embodiments of theinvention.

At least one embodiment of the invention further relates to a method forregulating the temperature of a converter material of an X-ray detectoraccording to the invention comprising:

determining a first temperature, comparing the first temperature with apredetermined second temperature value, and adjusting a current passingthrough an electrically conductive heating layer to regulate thetemperature of the converter material. In the determination step, afirst temperature is determined or measured, for example on the side ofthe readout and/or the evaluation unit that faces the converter materialor in the readout and/or the evaluation unit. In the comparison step,the first temperature is compared with the predetermined secondtemperature, by means, for example, of a comparator in the readoutand/or the evaluation unit. The second temperature can be a yardstick ora comparative value for a temperature in the converter material. In theadjustment step, the current passing through the electrically conductiveheating layer for regulating the temperature or regulating thetemperature of the converter material is adjusted.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments of the invention are described in greater detailhereinafter in connection with the drawings. The drawings show:

FIG. 1 in diagram form, is a concept for an X-ray detector according toa first embodiment;

FIG. 2 in diagram form, is a concept for an X-ray detector according toa second embodiment;

FIG. 3 in diagram form, is a concept for an X-ray detector according toa third embodiment;

FIG. 4 in diagram form, is a concept for an X-ray detector according toa fourth embodiment;

FIG. 5 in diagram form, is a concept for an electrically conductive meshaccording to an embodiment of the invention;

FIG. 6 in diagram form, is a concept for a further electrode accordingto an embodiment of the invention;

FIG. 7 in diagram form, is a detector module comprising an arrangementof X-ray detectors according to an embodiment of the invention;

FIG. 8 in diagram form, is a representation of a computer tomographaccording to an embodiment of the invention; and

FIG. 9 in diagram form, is a representation of a method according to anembodiment of the invention.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

In the following, embodiments of the invention are described in detailwith reference to the accompanying drawings. It is to be understood thatthe following description of the embodiments is given only for thepurpose of illustration and is not to be taken in a limiting sense. Itshould be noted that the drawings are to be regarded as being schematicrepresentations only, and elements in the drawings are not necessarilyto scale with each other. Rather, the representation of the variouselements is chosen such that their function and general purpose becomeapparent to a person skilled in the art.

The drawings are to be regarded as being schematic representations andelements illustrated in the drawings are not necessarily shown to scale.Rather, the various elements are represented such that their functionand general purpose become apparent to a person skilled in the art. Anyconnection or coupling between functional blocks, devices, components,or other physical or functional units shown in the drawings or describedherein may also be implemented by an indirect connection or coupling. Acoupling between components may also be established over a wirelessconnection. Functional blocks may be implemented in hardware, firmware,software, or a combination thereof.

Various example embodiments will now be described more fully withreference to the accompanying drawings in which only some exampleembodiments are shown. Specific structural and functional detailsdisclosed herein are merely representative for purposes of describingexample embodiments. Example embodiments, however, may be embodied invarious different forms, and should not be construed as being limited toonly the illustrated embodiments. Rather, the illustrated embodimentsare provided as examples so that this disclosure will be thorough andcomplete, and will fully convey the concepts of this disclosure to thoseskilled in the art. Accordingly, known processes, elements, andtechniques, may not be described with respect to some exampleembodiments. Unless otherwise noted, like reference characters denotelike elements throughout the attached drawings and written description,and thus descriptions will not be repeated. The present invention,however, may be embodied in many alternate forms and should not beconstrued as limited to only the example embodiments set forth herein.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, components, regions,layers, and/or sections, these elements, components, regions, layers,and/or sections, should not be limited by these terms. These terms areonly used to distinguish one element from another. For example, a firstelement could be termed a second element, and, similarly, a secondelement could be termed a first element, without departing from thescope of example embodiments of the present invention. As used herein,the term “and/or,” includes any and all combinations of one or more ofthe associated listed items. The phrase “at least one of” has the samemeaning as “and/or”.

Spatially relative terms, such as “beneath,” “below,” “lower,” “under,”“above,” “upper,” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the device in use or operation in addition tothe orientation depicted in the figures. For example, if the device inthe figures is turned over, elements described as “below,” “beneath,” or“under,” other elements or features would then be oriented “above” theother elements or features. Thus, the example terms “below” and “under”may encompass both an orientation of above and below. The device may beotherwise oriented (rotated 90 degrees or at other orientations) and thespatially relative descriptors used herein interpreted accordingly. Inaddition, when an element is referred to as being “between” twoelements, the element may be the only element between the two elements,or one or more other intervening elements may be present.

Spatial and functional relationships between elements (for example,between modules) are described using various terms, including“connected,” “engaged,” “interfaced,” and “coupled.” Unless explicitlydescribed as being “direct,” when a relationship between first andsecond elements is described in the above disclosure, that relationshipencompasses a direct relationship where no other intervening elementsare present between the first and second elements, and also an indirectrelationship where one or more intervening elements are present (eitherspatially or functionally) between the first and second elements. Incontrast, when an element is referred to as being “directly” connected,engaged, interfaced, or coupled to another element, there are nointervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between,” versus “directly between,” “adjacent,” versus“directly adjacent,” etc.).

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of exampleembodiments of the invention. As used herein, the singular forms “a,”“an,” and “the,” are intended to include the plural forms as well,unless the context clearly indicates otherwise. As used herein, theterms “and/or” and “at least one of” include any and all combinations ofone or more of the associated listed items. It will be furtherunderstood that the terms “comprises,” “comprising,” “includes,” and/or“including,” when used herein, specify the presence of stated features,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items. Expressionssuch as “at least one of,” when preceding a list of elements, modify theentire list of elements and do not modify the individual elements of thelist. Also, the term “exemplary” is intended to refer to an example orillustration.

When an element is referred to as being “on,” “connected to,” “coupledto,” or “adjacent to,” another element, the element may be directly on,connected to, coupled to, or adjacent to, the other element, or one ormore other intervening elements may be present. In contrast, when anelement is referred to as being “directly on,” “directly connected to,”“directly coupled to,” or “immediately adjacent to,” another elementthere are no intervening elements present.

It should also be noted that in some alternative implementations, thefunctions/acts noted may occur out of the order noted in the figures.For example, two figures shown in succession may in fact be executedsubstantially concurrently or may sometimes be executed in the reverseorder, depending upon the functionality/acts involved.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which example embodiments belong. Itwill be further understood that terms, e.g., those defined in commonlyused dictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Before discussing example embodiments in more detail, it is noted thatsome example embodiments may be described with reference to acts andsymbolic representations of operations (e.g., in the form of flowcharts, flow diagrams, data flow diagrams, structure diagrams, blockdiagrams, etc.) that may be implemented in conjunction with units and/ordevices discussed in more detail below. Although discussed in aparticularly manner, a function or operation specified in a specificblock may be performed differently from the flow specified in aflowchart, flow diagram, etc. For example, functions or operationsillustrated as being performed serially in two consecutive blocks mayactually be performed simultaneously, or in some cases be performed inreverse order. Although the flowcharts describe the operations assequential processes, many of the operations may be performed inparallel, concurrently or simultaneously. In addition, the order ofoperations may be re-arranged. The processes may be terminated whentheir operations are completed, but may also have additional steps notincluded in the figure. The processes may correspond to methods,functions, procedures, subroutines, subprograms, etc.

Specific structural and functional details disclosed herein are merelyrepresentative for purposes of describing example embodiments of thepresent invention. This invention may, however, be embodied in manyalternate forms and should not be construed as limited to only theembodiments set forth herein.

Although described with reference to specific examples and drawings,modifications, additions and substitutions of example embodiments may bevariously made according to the description by those of ordinary skillin the art. For example, the described techniques may be performed in anorder different with that of the methods described, and/or componentssuch as the described system, architecture, devices, circuit, and thelike, may be connected or combined to be different from theabove-described methods, or results may be appropriately achieved byother components or equivalents.

At least one embodiment of the invention relates to a counting X-raydetector comprising, in a stacked array, a converter material forconverting X-ray radiation into electrical charges, and an electrode.The electrode is electrically conductively connected to the convertermaterial. The electrode is designed to be at least partly transparent.The electrode has the following layers: an electrically conductivecontact layer, an electrically conductive first intermediate layer, anelectrically conductive high voltage layer, a second intermediate layer,and an electrically conductive heating layer.

The inventors have identified that a need exists for an electrode for anX-ray detector, which is transparent or has low absorption, for exampleto X-ray radiation, UV, IR or visible light, which at the same time iseconomical to produce and does not comprise any material that is rare orof limited availability. The inventors have further identified that thetemperature stabilization via a heating layer in direct thermalconnection with the converter material allows an accuracy of temperatureof up to less than 1K or equal to 1K exactly. The inventors haveidentified that it is possible to stabilize the temperature with anelectrode, to apply a high voltage to the converter material, and todesign the electrode such that the converter material can beilluminated.

The X-ray detector may be a counting X-ray detector. The X-ray detectorcomprises a directly-converting converter material, for example CdTe,CZT, CdZnTeSe, CdTeSe, CdMnTe, InP, TlBr₂, HgI₂ or GaAs. The convertermaterial and the readout or/and the electronic evaluation unit can bearranged in a stacked array. On the side of the converter material thatfaces away from the beam, at least one readout contact can be providedas an anode. The anode can be subdivided in a pixelated manner. On theside of the converter material that faces the beam, an electrode isprovided as a cathode. The electrode is planar in design. A sensor cancomprise the converter material, the electrode and the anode.

The electrode and the converter material may be arranged in a stackedarray. The electrode and the converter material can be electricallyconnected to each other in a planar manner. The electrode and theconverter material can at least approximately have the same planarextent.

The electrode may be designed to be at least partly transparent. Theelectrode can be at least partly transparent to or have low absorptionof, for example UV, IR or visible light. Preferably the electrode can beat least partly transparent to or have low absorption of, for example,X-ray radiation and IR light. The electrode can be designed to be atleast partly transparent to UV, IR or visible light, such that a maximumof 30 percent of the irradiated UV, IR or visible light can be absorbed.The electrode can be at least partly electrically conductive.

The electrode comprises a plurality of layers in a stacked array. Thelayers can be connected to each other in a planar manner. The electrodecan comprise the following layers in the following sequence: theelectrically conductive contact layer, the electrically conductive firstintermediate layer, the electrically conductive high voltage layer, thesecond intermediate layer, and the electrically conductive heatinglayer.

The contact layer can be electrically conductively connected directly tothe converter material. The contact layer can be applied directly ontothe converter material. The first intermediate layer can be applieddirectly onto the contact layer. The high voltage layer can be applieddirectly onto the first intermediate layer. The second intermediatelayer can be applied directly onto the high voltage layer. The heatinglayer can be applied directly onto the second intermediate layer.Applying can be understood as deposition, vapor deposition, adhesivebonding, applying, mounting, brushing or other methods for applyingcoatings.

The properties of the converter material for the detection of ionizingradiation, of X-ray radiation for example, can be optimized byadditional irradiation of IR, UV or visible light, for example from theside that faces towards the beam. The electrode can be at least partlytransparent to IR, UV, or visible light and the X-ray detector canadvantageously be optimized via additional irradiation of IR, UV, orvisible light.

The electrically conductive contact layer can be a thin metallic layer,comprising for example, platinum, indium, molybdenum, tungsten,ruthenium, rhodium, gold, silver or aluminum. The electricallyconductive contact layer can be a thin metallic layer. The contact layercan be designed to be at least partly transparent. The contact layer canhave a thickness of a maximum of 250 nm, preferably a maximum of 200 nm,and particularly preferably a maximum of 150 nm. The contact layer canbe designed to be porous, the pores in the contact layer beingtransparent to electromagnetic radiation, in particular to IR and X-rayradiation. The contact layer can be designed in the form of a mesh.

The electrically conductive first intermediate layer can be designed tobe at least partly transparent. The first intermediate layer can be anelectrically conductive adhesive tape. The electrically conductive firstintermediate layer can comprise an electrically conductive adhesive. Theelectrically conductive first intermediate layer can comprise a bondingagent and at least one electrically conductive filler element embeddedtherein. The bonding agent can be designed to be at least partlytransparent or semi-transparent, preferably transparent, toelectromagnetic radiation, in particular to X-ray radiation and IRlight. The filler element can form an electrically conductive connectionbetween the contact layer and the high voltage layer. The filler elementcan be designed from a metal. The first intermediate layer can have adegree of absorption of 75 percent maximum, preferably 60 percentmaximum, particularly preferably 50 percent maximum and in most casespreferably have a maximum of 40 percent of the intensity of IR, UV, orvisible light.

The electrically conductive high voltage layer can be designed as a TCOlayer. The TCO layer can be designed from at least one material in thelist that follows: indium tin oxide, indium oxide, tin oxide, zincoxide, cadmium oxide, poly 3,4-ethylene dioxythiophene, polystyrenesulfonate, carbon nanotubes or polyaniline derivatives. The TCO layercan be designed from at least one pure or a doped material.

The electrically conductive high voltage layer can be designed in theform of a mesh. The electrically conductive high voltage layer can bedesigned as an electrically conductive mesh, in particular as a metallicmesh. The electrically conductive mesh can comprise copper, silver,nickel, gold or suchlike. The electrically conductive mesh can bedesigned to be so thin that the electrically conductive mesh istransparent to X-ray radiation. The electrically conductive mesh, inparticular the crosspieces of the electrically conductive mesh, can bedesigned such that the mesh is not transparent to UV, IR, or visiblelight. The electrically conductive mesh can be designed to be at leastpartly transparent to UV, IR, or visible light, such that a maximum of30 percent of the irradiated UV, IR, or visible light is absorbed. Theelectrode can be designed to be at least partly transparent to UV, IR,or visible light, such that a maximum of 30 percent of the irradiationof UV, IR, or visible light is absorbed. The electrically conductivemesh can form a regular or an irregular pattern. The spaces between thecrosspieces of the mesh can be small enough for sufficient fillerelements in the first intermediate layer to have an electricallyconductive contact with the electrically conductive mesh.

Advantageously, the electrically conductive mesh can be more economicalin production than the deposition of TCO layers. Advantageously, theproduction of an electrode comprising an electrically conductive meshcan be more economical than the production of an electrode comprising aTCO layer.

The second intermediate layer can be electrically conductive. The secondintermediate layer can be electrically insulating or non-conductive. Thesecond intermediate layer can preferably be electrically insulating. Thesecond intermediate layer can be an adhesive strip or comprise anadhesive. The second intermediate layer can be similar in design to thefirst intermediate layer. The second intermediate layer can comprise abonding agent. The second intermediate layer can comprise at least oneelectrically conductive filler element embedded in the bonding agent.

The electrically conductive heating layer can be designed as a TCO layeror as an electrically conductive mesh. Due to its electrical resistance,the heating layer can be used as a heating element, in that the electriccurrent passing through the heating layer is monitored or controlled orregulated. To regulate the electric current through the heating layer, afirst temperature measured on the surface of the readout and/or theevaluation unit, for example on an integrated circuit (an ApplicationSpecific Integrated Circuit, ASIC), can be used. The first temperaturecan be compared with a predetermined second temperature. The comparisonof the first temperature with the second temperature can be carried outin a comparator in the readout and/or the evaluation unit, for examplein an integrated circuit (an Application Specific Integrated Circuit,ASIC).

In the event of a first temperature that is lower compared to the secondtemperature, the electric current or current flow through the heatinglayer can be increased. In the event of a first temperature that ishigher compared to the second temperature, the electric current orcurrent flow through the heating layer can be reduced. In the event of afirst temperature that is the same compared to the second temperature,the electric current or current flow through the heating layer can beincreased or reduced or maintained at a constant value depending on thedesign of the comparator. A plurality of heating layers can be arrangedsuch that they are spatially separated from one another inside theelectrode, it being possible to regulate the currents passing throughthe heating layers by using different electric circuits or a sharedelectric circuit. A plurality of electrodes can be arranged on theconverter material, it being possible, for example, for the currentspassing through the heating layers to be regulated using differentelectric circuits or a shared electric circuit.

The electrical resistance of the converter material can change with theflow of the incident ionizing radiation. The electric current in theconverter material can change with the flow of the incident ionizingradiation. As a result thereof, the dissipation and the temperature ofthe converter material can change. The change in the temperature in theconverter material can lead to a change in the count rate or/and theenergy resolution of the X-ray detector. As a result thereof, unwantedartifacts can be caused in the reconstructed image. A high degree ofthermal stability is therefore desirable.

Advantageously, the heat flow can ensue from the side facing the beam.Advantageously, the heat flow can emanate from a heating element indirect thermal contact with the converter material. Advantageously, aparticularly regular heating of the converter material is possible.Advantageously, the heat flow can emanate from a heating elementencompassed by the electrode. Advantageously, the heat flow or the heatcan spread in the converter material. Advantageously, a homogeneoustemperature or temperature distribution can be achieved in the convertermaterial. Advantageously, the heat flow can spread from the convertermaterial across the soldered or electrically conductive adhesive bond tothe readout- and/or the evaluation unit, for example to an integratedcircuit (an Application Specific Integrated Circuit, ASIC), and furtherspread to the further substrate. Advantageously, the heat flow emanatingfrom the heating layer can be used more effectively to regulate thetemperature of the converter material than a heat flow that emanatesfrom heating elements in the further substrate, on the side of thefurther substrate that faces away from the beam or in the readout and/orthe evaluation unit.

Advantageously, the thermal management or the heat flow can besimplified as compared with the disadvantageous array of heatingelements or cooling elements in the further substrate, on the side ofthe further substrate that faces away from the beam, or in the readoutand/or the evaluation unit. Advantageously, an improved temperaturestability can be achieved since, due to the direct array of theelectrode comprising the heating layer, the chronologically fast rapidtemperature changes, which are typical, of computer tomography forexample, can be counteracted. The heat flow that emanates from heatingelements or cooling elements in the further substrate, on the side ofthe further substrate that faces away from the beam or in the readoutand/or the evaluation unit can be chronologically more slowly pronouncedthan the heat flow emanating from the electrode comprising the heatinglayer. Advantageously, a temperature stability of 1K or less can beachieved in the converter material.

According to one embodiment of the invention, the electrode furthercomprises a first carrier protection layer and/or a second carrierprotection layer.

According to one embodiment of the invention, the electrode furthercomprises a first carrier protection layer arranged in the region of thehigh voltage layer and/or a second carrier protection layer arranged inthe region of the heating layer.

The electrode can comprise the following layers in the followingsequence: the electrically conductive contact layer, the electricallyconductive first intermediate layer, the electrically conductive highvoltage layer, the first carrier protection layer, the secondintermediate layer, the electrically conductive heating layer, and thesecond carrier protection layer. The contact layer can be electricallyconductively connected directly to the converter material. The contactlayer can be applied directly onto the converter material. The firstintermediate layer can be applied directly onto the contact layer. Thehigh voltage layer can be applied directly onto the first intermediatelayer. The first carrier protection layer can be applied directly ontothe high voltage layer. The second intermediate layer can be applieddirectly onto the first carrier protection layer or onto the highvoltage layer. The heating layer can be applied directly onto the secondintermediate layer. The second carrier protection layer can be applieddirectly onto the heating layer.

The first carrier protection layer and/or the second carrier protectionlayer can be a carrier foil. The first carrier protection layer and/orthe second carrier protection layer can be designed, for example, frompolyethylene terephthalate, polyethylene terephthalate glycols,polypropylene, polyethylene, polyvinyl chloride or suchlike. The firstcarrier protection layer and/or the second carrier protection layer canbe designed to be electrically insulating or non-conductive.

According to one embodiment of the invention, an electric circuit isprovided to apply a current to the electrically conductive heating layeras a function of a first temperature that is acquired in the X-raydetector.

The electric circuit can be provided in the readout and/or theevaluation unit, on the further substrate, inside or outside the X-raydetector. The electric circuit can preferably be provided in theevaluation and/or readout unit or in the electrode. The current can beregulated as a function of the first temperature. The current can beregulated as a function of the result of the comparison in a comparator.A current can be applied to the heating layer. The circuit can beprovided for any X-ray detector. Advantageously, the current can beregulated as a function of the first temperature. Advantageously, thecurrent can be applied to the converter material for any X-ray detector,irrespective of further X-ray detectors.

According to one embodiment of the invention, the electricallyconductive high voltage layer or the electrically conductive heatinglayer is designed as an electrically conductive mesh, in particular as ametallic mesh. Advantageously, the electrically conductive mesh can bemore economical in production than the deposition of TCO layers.Advantageously, the production of an electrode comprising anelectrically conductive mesh can be more economical than the productionof an electrode comprising a TCO layer.

According to one embodiment of the invention, the electricallyconductive high voltage layer or the electrically conductive heatinglayer is designed as a TCO layer. Advantageously, the TCO layer can behomogeneously transparent in a planar manner or slightly absorbent.Advantageously, the electrically conductive connection to the firstintermediate layer can be produced reliably in a planar manner.

According to one embodiment of the invention, the X-ray detectorcomprises a temperature sensor to acquire the first temperature on aside of the converter material that faces away from the electrode. Thetemperature sensor can be encompassed by the readout and/or theevaluation unit or the further substrate. The temperature sensor can beconfigured on the side of, on top of, in, or under the readout and/orthe evaluation unit or the further substrate. The temperature sensor canbe designed to be between the converter material and the readout and/orthe evaluation unit. The temperature sensor can be designed to be indirect thermal connection with the converter material. The temperaturesensor can be arranged directly on the converter material. A temperaturediode can be provided as a temperature sensor in the electrode, thesignal from which can be evaluated outside the electrode.Advantageously, the temperature sensor can determine a firsttemperature. The temperature sensor can determine the first temperaturein its position or its location. The first temperature can represent,for example, a temperature on the side of the readout and/or theevaluation unit that faces towards the converter material or in theelectrode. Advantageously, the first temperature can represent ayardstick for the temperature of the converter material.

According to one embodiment of the invention, the X-ray detector furthercomprises a comparator to compare the first temperature with apredeterminable second temperature value. Advantageously, the firsttemperature can be compared with a predetermined second temperaturevalue in the X-ray detector. Advantageously, the comparison of thetemperature can be carried out for each X-ray detector irrespective offurther X-ray detectors.

According to one embodiment of the invention, the converter materialcomprises the element cadmium. Advantageously, the converter materialcan comprise suitable or optimal absorption properties for medicalimaging, in particular with a computer tomograph.

According to one embodiment of the invention, the electricallyconductive mesh comprises at least one of the following elements:copper, silver, nickel, or gold. Advantageously, the electricallyconductive mesh can be suitable for applying a high voltage.Advantageously, the electrically conductive mesh can be suitable forapplying a current. Advantageously, the electrically conductive mesh cancomprise a suitable electrical resistance to heat the convertermaterial. Advantageously, the electrically conductive mesh can beproduced by known and economical methods.

According to one embodiment of the invention, the X-ray detector furthercomprises an illumination device to illuminate the converter material.The X-ray detector can include an illumination device for illuminationor for additional irradiation. The medical device can include anillumination device for illumination or for additional irradiation. Theillumination or the additional irradiation can include the illuminationwith a UV or IR light source or a light source for visible light. Theillumination device can for example be designed as a light conductor ordiffusor, into which UV, IR, or visible light can be injected.

According to one embodiment of the invention, the electricallyconductive mesh absorbs less than 30 percent of the amount of light thatis beamed onto the converter material by the illumination device. Theamount of light can relate to the amount of UV, IR, or visible light.Advantageously, the properties of the converter material can beoptimized by the additional irradiation or illumination.

According to one embodiment of the invention, the contact layercomprises one of the following elements: platinum, indium, molybdenum,tungsten, ruthenium, rhodium, gold, silver or aluminum. Advantageously,the contact layer can be suitable for forming an electrically conductiveconnection. Advantageously, the high voltage can be applied to theconverter material via the contact layer.

According to one embodiment of the invention, the contact layer isdesigned to be at least partly transparent. The contact layer can bedesigned to be at least partly transparent to UV, IR, or visible light.The contact layer can be designed to be at least partly transparent toionizing radiation, for example, to X-ray radiation. The contact layercan preferably be transparent or have low absorption to ionizingradiation. Advantageously, the influence of the contact layer on theimaging properties can be slight or negligible. Advantageously, thecontact layer can allow an additional irradiation of the convertermaterial with UV, IR, or visible light in order to optimize the imaging.

According to one embodiment of the invention, the electricallyconductive first intermediate layer comprises an bonding agent and anelectrically conductive filler. The second intermediate layer can bedesigned in a similar manner to the first intermediate layer.Advantageously, the first intermediate layer can be used to affix thehigh voltage layer. Advantageously, the first intermediate layer canform an electrically conductive connection between the high voltagelayer and the contact layer.

According to one embodiment of the invention, an electrically conductiveconnection is configured between the electrode and a voltage source. Anelectrically conductive connection can be configured between an externalvoltage source and the electrode or the further electrode.Advantageously, a high voltage can be applied to the electrode and henceto the converter material.

According to one embodiment of the invention, the electricallyconductive connection includes a continuation of the electricallyconductive high voltage layer. The electrically conductive connectioncan be configured as a continuation of the high voltage layer. Theelectrically conductive connection can include the first carrierprotection layer. The continuation of the high voltage layer can bepartly or completely covered by the first carrier protection layer.Advantageously, the first carrier protection layer can comprise anelectrically insulating or mechanically supportive function.Advantageously, the voltage source can be connected to a connectionpoint, by for example a soldered connection, or by few connection pointswith the high voltage layer. Advantageously, an appropriate mechanicalstability of the electrically conductive connection between the voltagesource and the electrode or the high voltage layer can be guaranteed.The electrically conductive connection between the power source and theheating layer can be configured as a continuation of the electricallyconductive heating layer.

At least one embodiment of the invention further relates to a countingX-ray detector comprising, in a stacked array, a converter material forconverting X-ray radiation into electrical charges and a furtherelectrode. The further electrode is electrically connected to theconverter material. The further electrode is designed to be at leastpartly transparent. The further electrode comprises the followinglayers: an electrically conductive contact layer, an electricallyconductive first intermediate layer and an electrically conductive highvoltage layer, which is designed in the shape of a mesh. The countingX-ray detector can further comprise a first carrier protection layer.

On the side of the converter material that faces the beam, the furtherelectrode is provided as a cathode. The further electrode is planar indesign. A sensor can include the converter material, the furtherelectrode and the anode. The further electrode and the convertermaterial are arranged in a stacked array. The further electrode and theconverter material are electrically connected to each other over a broadarea. The further electrode and the converter material can at leastapproximately have the same planar expanse.

The further electrode is designed to be at least partly transparent. Thefurther electrode can be at least partly transparent or have lowabsorption, for example to X-ray radiation, UV, IR, or visible light.The further electrode can be at least partly transparent or have lowabsorption to X-ray radiation and IR light. The further electrode is atleast partly transparent to IR, UV, or visible light and the propertiesof the converter material can be optimized advantageously by additionalirradiation of IR, UV, or visible light. The further electrode can bedesigned to be at least partly transparent to UV, IR, or visible light,such that a maximum of 30 percent of the irradiation of UV, IR, orvisible light can be absorbed. The further electrode can be at leastpartly electrically conductive. The further electrode comprises aplurality of layers in a stacked array. The layers are connected to eachother in a planar manner. The further electrode can comprise thefollowing layers in the following sequence: the electrically conductivecontact layer, the electrically conductive first intermediate layer, theelectrically conductive high voltage layer, and the first carrierprotection layer. The contact layer can be electrically conductivelyconnected directly to the converter material. The contact layer can beapplied directly on the converter material. The first intermediate layercan be applied directly on the contact layer. The high voltage layer canbe applied directly onto the first intermediate layer. The first carrierprotection layer can be applied directly onto the high voltage layer.

The electrically conductive high voltage layer in the further electrodeis designed in the form of a mesh. The high voltage layer can be anelectrically conductive mesh. Advantageously, the production of anelectrode comprising an electrically conductive mesh can be moreeconomical than the production of an electrode comprising a TCO layer.

At least one embodiment of the invention further relates to a medicaldevice comprising an X-ray detector according to at least one embodimentof the invention. The advantages of the X-ray detector according toembodiments of the invention that comprises the electrode can betransferred to the medical device according to embodiments of theinvention.

Advantageously, unwanted artifacts in the reconstructed image can bereduced by the high thermal stability of 1K or less. The properties ofthe converter material can be optimized via additional irradiation ofIR, UV, or visible light onto the converter material, such that theimaging is advantageously improved.

The advantages of embodiments of the X-ray detector comprising thefurther electrode can be transferred to embodiments of the medicaldevice according to the invention. Advantageously, the quality of theimaging can be optimized via additional irradiation of IR, UV, orvisible light onto the converter material.

At least one embodiment of the invention further relates to a method forregulating the temperature of a converter material of an X-ray detectoraccording to the invention comprising:

determining a first temperature, comparing the first temperature with apredetermined second temperature value, and adjusting a current passingthrough an electrically conductive heating layer to regulate thetemperature of the converter material. In the determination step, afirst temperature is determined or measured, for example on the side ofthe readout and/or the evaluation unit that faces the converter materialor in the readout and/or the evaluation unit. In the comparison step,the first temperature is compared with the predetermined secondtemperature, by means, for example, of a comparator in the readoutand/or the evaluation unit. The second temperature can be a yardstick ora comparative value for a temperature in the converter material. In theadjustment step, the current passing through the electrically conductiveheating layer for regulating the temperature or regulating thetemperature of the converter material is adjusted.

Advantageously, the temperature in the converter material can becontrolled, adjusted or regulated.

FIG. 1 shows by way of example an embodiment of the X-ray detector 1 asper the invention according to a first embodiment. The counting X-raydetector 1 comprises in a stacked array a converter material 2 forconverting X-ray radiation into electric charges, and an electrode 3.The electrode 3 is electrically conductively connected to the convertermaterial 2. The electrode 3 and the converter material 2 are arranged ina stacked array. The electrode 3 and the converter material 2 areelectrically connected to one another in a planar manner. The electrode3 and the converter material 2 have at least approximately the sameplanar expanse. The electrode 3 is designed to be at least partlytransparent. The electrode 3 is at least partly transparent or has lowabsorption, for example to X-ray radiation, UV, IR, or visible light.The electrode 3 is preferably at least partly transparent or has lowabsorption to X-ray radiation and IR light. The electrode 3 is designedto be at least partly transparent to UV, IR, or visible light such thata maximum of 30 percent of the irradiation of UV, IR, or visible lightis absorbed. The properties of the converter material 2 for thedetection of X-ray radiation are optimized by additional irradiation ofIR, UV, or visible light from the side that faces the beam. Theelectrode 3 is at least partly electrically conductive.

The electrode 3 comprises a plurality of layers in a stacked array. Theelectrode 3 comprises the following layers in the following sequence: anelectrically conductive contact layer 4, an electrically conductivefirst intermediate layer 5, an electrically conductive high voltagelayer 6, a first carrier protection layer 7, a second intermediate layer8, an electrically conductive heating layer 9, and a second carrierprotection layer 10. The contact layer 4 is electrically conductivelyconnected directly to the converter material 2. The contact layer 4 isapplied directly onto the converter material 2. The first intermediatelayer 5 is applied directly onto the contact layer 4. The high voltagelayer 6 is applied directly onto the first intermediate layer 5. Thefirst carrier protection layer 7 is applied directly onto the highvoltage layer 6. The second intermediate layer 8 is applied directlyonto the first carrier protection layer 7. The heating layer 9 isapplied directly onto the second intermediate layer 8. The secondcarrier protection layer 10 is applied directly onto the heating layer9. Applying can be understood as deposition, vapor deposition, adhesivebonding, applying, mounting, brushing or other methods for applyinglayers.

On the side that faces the beam, the converter material 2 comprisessoldered connections 69, in order to form an electrically conductiveconnection to the readout and/or evaluation unit 59. The readout and/orthe evaluation unit 59 have/has a temperature sensor 12 and a comparator13. The electrically conductive connection 14 to the voltage source 15is a continuation of the high voltage layer 6 and of the first carrierprotection layer 7. The voltage source 15 and the electricallyconductive connection 14 or the high voltage layer 6 are connected, forexample, via a soldered connection, an indirect connection, a plugconnection or an electrically conductive bond.

The electrically conductive contact layer 4 is a thin metallic layer,comprising, for example, platinum, indium, molybdenum, tungsten,ruthenium, rhodium, gold, silver or aluminum. The electricallyconductive contact layer 4 is a thin foil layer. The contact layer 4 isdesigned to be at least partly transparent. The contact layer 4 has athickness of a maximum of 250 nm, preferably a maximum of 200 nm,particularly preferably a maximum of 150 nm. The contact layer 4 can bedesigned to be porous, the pores in the contact layer 4 beingtransparent to electromagnetic radiation, in particular to IR and X-rayradiation. The contact layer 4 can alternatively be designed in the formof a network.

The electrically conductive first intermediate layer 5 is designed to beat least partly transparent. The first intermediate layer 5 is anelectrically conductive adhesive strip or comprises an electricallyconductive adhesive. The electrically conductive first intermediatelayer 5 comprises a bonding agent 5 a and at least one electricallyconductive filler element 5 b embedded therein. The bonding agent 5 a isat least semi-transparent, preferably transparent, to electromagneticradiation, in particular to X-ray radiation and IR light. The fillerelement 5 b forms an electrically conductive connection between thecontact layer 4 and the high voltage layer 6. The filler element 5 b isdesigned from a metal. The first intermediate layer 5 has a maximumdegree of absorption of 75 percent, preferably a maximum of 60 percent,particularly preferably a maximum of 50 percent, and most preferably amaximum of 40 percent of the intensity of IR, UV, or visible light.

The electrically conductive high voltage layer 6 is configured as a TCOlayer or in the form of a mesh. The TCO layer can be designed from atleast one material in the following list: indium tin oxide, indiumoxide, tin oxide, zinc oxide, cadmium oxide, poly 3,4-ethylenedioxythiophene, polystyrene sulfonate, carbon nanotubes or polyanilinederivatives. The TCO layer can be designed from at least one pure or adoped material. The electrically conductive high voltage layer 6 can bedesigned in the form of an electrically conductive mesh 16. Theelectrically conductive mesh 16 can comprise copper, silver, nickel,gold or suchlike. The electrically conductive mesh 16 can be designed tobe so thin that the electrically conductive mesh 16 is transparent toX-ray radiation. The electrically conductive mesh 16 can be designedsuch that it is not transparent to UV, IR, or visible light. Theelectrically conductive mesh 16 can be designed to be at least partlytransparent to UV, IR, or visible light, such that a maximum of 30percent of the irradiation of UV, IR, or visible light is absorbed. Theelectrically conductive mesh 16 can form a regular or an irregularpattern. The spaces between the crosspieces of the electricallyconductive mesh 16 can be small enough for sufficient filler elements 5b in the first intermediate layer 5 to have an electrically conductivecontact with the electrically conductive mesh 16.

At least the spaces between the crosspieces of the electricallyconductive mesh 16 can be designed to be transparent.

The first carrier protection layer 7 is a carrier foil. The firstcarrier protection layer 7 and/or the second carrier protection layer 10are/is designed, for example, from polyethylene terephthalate,polyethylene terephthalate glycols, polypropylene, polyethylene,polyvinyl chloride or suchlike. The first carrier protection layer 7and/or the second carrier protection layer 10 are/is designed to beelectrically insulating or non-conductive.

The second intermediate layer 8 can be electrically conductive orelectrically insulating or non-conductive. The second intermediate layer8 is an adhesive strip or comprises an adhesive. The second intermediatelayer 8 can be designed like the first intermediate layer; for example,it can have the same bonding agent 5 a or the same thickness as thefirst intermediate layer 5. The second intermediate layer 8 comprises abonding agent 5 a. The second intermediate layer 8, if it is designed tobe electrically conductive, can comprise at least one electricallyconductive filler element 5 b embedded in the bonding agent 5 a.

The electrically conductive heating layer 9 is designed as a TCO layeror as an electrically conductive mesh 16. The heating layer 9 isconnected to a power source 11 via a further electrically conductiveconnection 11a. The further electrically conductive connection 11 a tothe power source 11 is electrically connected to a continuation of theheating layer 9. The power source 11 or the electrically conductiveconnection 11 a and the continuation of the heating layer 9 areconnected, for example, via a soldered connection, an indirectconnection, a plug connection or an electrically conductive bond. Due toits electrical resistance, the heating layer 9 is used as a heatingelement, in that the electric current passing through the heating layer9 is monitored or controlled or regulated.

To regulate the electric current passing through the heating layer 9, afirst temperature measured on the surface of the readout and/or theevaluation unit 59, for example on an integrated circuit (an ApplicationSpecific Integrated Circuit, ASIC), is used. The first temperature iscompared with a predetermined second temperature. There is a connectionbetween the comparator 13 and the power source 11. The current flow orthe power source 11 is controlled via a signal based on the outputsignal from the comparator 13. The output signal from the comparator 13can be read off by way of a data readout from the readout and/or theevaluation unit 59. The signal based on the output signal from thecomparator 13 can be processed using a further evaluation unit and usedto control the current flow or the power source 11. The current can beapplied to the heating layer 9 via an electric circuit.

The comparison of the first temperature with the second temperature iscarried out in a comparator 13 in the readout and/or the evaluation unit59, for example in an integrated circuit (an Application SpecificIntegrated Circuit, ASIC). In the event of a first temperature that islower compared to the second temperature, the electric current orcurrent flow through the heating layer 9 is increased. In the event of afirst temperature that is higher compared to the second temperature, theelectric current or current flow through the heating layer 9 is reduced.In the event of a first temperature that is the same compared to thesecond temperature, the electric current or current flow through theheating layer 9 can be increased or reduced or maintained at a constantvalue, depending on the design of the comparator 13.

In a further embodiment (not shown), the electrode comprises at leastthe following layers: an electrically conductive contact layer 4, anelectrically conductive first intermediate layer 5, an electricallyconductive high voltage layer 6, a second intermediate layer 8, and anelectrically conductive heating layer 9. The second intermediate layer 8is applied directly onto the high voltage layer 6. The secondintermediate layer 8 is electrically insulating.

FIG. 2 shows, by way of example, an embodiment of the X-ray detector 1according to the invention as per a second embodiment. The heat flow 17to the converter material 2 ensues from the side of the convertermaterial 2 that faces the beam. The heat flow 17 emanates from theheating layer 9 encompassed by the electrode 3, in direct thermalcontact with the converter material 2. The heat flow 17 or the heat canspread directly in the converter material 2. A homogeneous temperatureor temperature distribution will be achieved in the converter material2. The heat flow 17 spreads from the converter material 2 across thesoldered connections 69 or electrically conductive adhesive bond to thereadout and/or the evaluation unit 59, for example an integrated circuit(Application Specific Integrated Circuit, ASIC), and to the furthersubstrate 18. The heat flow 17 emanating from the heating layer 9 isused more effectively to regulate the temperature of the convertermaterial 2 than a heat flow 17 that emanates from heating elements inthe further substrate 18, on the side of the further substrate 18 thatfaces away from the beam or in the readout and/or the evaluation unit59.

An improved temperature stability is achieved since, due to the directarray of the electrode 3 comprising the heating layer 9, thechronologically rapid temperature changes, which are typical, forexample, of computed tomography, are counteracted. The heat flow 17 thatemanates from heating elements or cooling elements in the furthersubstrate 18, on the side of the further substrate 18 that faces awayfrom the beam or in the readout and/or the evaluation unit 59 can bechronologically more slowly pronounced than the heat flow 17 thatemanates from the electrode 3 comprising the heating layer 9. Atemperature stability of 1K or less is achieved in the convertermaterial 2.

FIG. 3 shows, by way of example, an embodiment of the X-ray detectoraccording to the invention 1 as per a third embodiment. The electricallyconductive connection 14 to the voltage source 15 and the furtherelectrically conductive connection 11 a to the power source 11 are ashared continuation of the high voltage layer 6, of the first carrierprotection layer 7, of the second intermediate layer 8, of the heatinglayer 9 and of the second carrier protection layer 10.

FIG. 4 shows, by way of example, an embodiment of an X-ray detector 1according to the invention as per a fourth embodiment. A view is shownonto the side of the X-ray detector 1 that faces the beam. The sharedcontinuation of the high voltage layer 6, of the first carrierprotection layer 7, of the second intermediate layer 8, of the heatinglayer 9 and of the second carrier protection layer 10 has a smallerwidth than the side of the electrode 3 that faces the voltage source 15.

FIG. 5 shows, by way of example, an embodiment of an electricallyconductive mesh 16 according to the invention. The electricallyconductive mesh 16 comprises at least one of the following metals:copper, silver, nickel, gold or suchlike. The electrically conductivemesh 16 can be designed to be so thin that the electrically conductivemesh 16 is transparent to X-ray radiation. The electrically conductivemesh 16 is designed to be at least partly transparent to UV, IR, orvisible light, such that a maximum of 30 percent of the irradiation ofUV, IR, or visible light is absorbed. The electrically conductive mesh16 can form a regular or an irregular pattern. The spaces between thecrosspieces of the electrically conductive mesh 16 can be small enoughfor sufficient filler elements 5 b in the first intermediate layer 5 tohave an electrically conductive contact with the electrically conductivemesh 6.

FIG. 6 shows, by way of example, an embodiment of a further electrode 3a according to the invention on a converter material 2 with a voltagesource 15. The counting X-ray detector 1 comprises in a stacked array aconverter material 2 for converting X-ray radiation into electriccharges, and a further electrode 3 a. On the side of the convertermaterial 2 facing the beam, the further electrode 3 a is provided as acathode. The further electrode 3 a is planar in design. The furtherelectrode 3 a and the converter material 2 are electrically connected toone another in a planar manner. The further electrode 3 a and theconverter material 2 can at least approximately have the same planarexpanse. The further electrode 3 a is designed to be at least partlytransparent. The further electrode 3 a can be at least partlytransparent or have low absorption, for example to X-ray radiation, UV,IR, or visible light. Preferably, the further electrode 3 a can be atleast partly transparent or have low absorption to X-ray radiation andIR light. The further electrode 3 a is at least partly transparent toIR, UV, or visible light and the properties of the converter material 2can be optimized via additional irradiation of IR, UV, or visible light.The further electrode 3 a can be designed to be at least partlytransparent to UV, IR, or visible light such that a maximum of 30percent of the irradiated UV, IR, or visible light is absorbed. Thefurther electrode 3 a can be at least partly electrically conductive.The further electrode 3 a comprises a plurality of layers in a stackedarray. The layers are connected to each other in a planar manner. Thefurther electrode 3 a comprises the following layers in the followingsequence: an electrically conductive contact layer 4, an electricallyconductive first intermediate layer 5, an electrically conductive highvoltage layer 5 that is designed in the form of a mesh and a firstcarrier protection layer 6. The contact layer 4 can be electricallyconnected directly to the converter material 2. The contact layer 4 isapplied directly onto the converter material 2. The first intermediatelayer 5 is applied directly onto the contact layer 4. The high voltagelayer 6 is applied directly onto the first intermediate layer 5. Thefirst carrier protection layer 7 is applied directly onto the highvoltage layer 6. The electrically conductive high voltage layer 6 of thefurther electrode 3 a is designed in the form of a mesh. The highvoltage layer 6 is an electrically conductive mesh 16.

FIG. 7 shows, by way of example, an embodiment of the detector module 51with an array of X-ray detectors 1 according to the invention. In apreferred embodiment, the X-ray detector 1 comprises a two-dimensionalmatrix or array consisting of a plurality of pixels or sub-pixels. Thenumber of sub-pixels can be for example in the region ranging from 100to several thousands. The X-ray detector 1 comprises a convertermaterial 2. The converter material 2 can be designed as a planar directconverter, comprising for example CdTe, CZT, CdZnTeSe, CdTeSe, CdMnTe,InP, TlBr₂, HgI₂, GaAs or other materials. The upper side of theconverter material 2 comprises an electrode 3 or a further electrode 3a. The underside of the converter material 2 comprises a two-dimensionalarray of contacts 56. The contacts 56 are connected via solderedconnections 69 to the readout contacts 57 and to the pixel electronics67 in the readout and/or evaluation unit 59. The soldered connections 69can be designed, for example, as bump bonds or soldered material inconjunction with copper pillars. The number of contacts 56, the numberof soldered connections 69, the number of readout contacts 57, and thenumber of pixel electronics 67 in the readout and/or evaluation unit 59is the same. The electric field between the electrode 3 or the furtherelectrode 3 a and a contact 56 determines a sensitive detection volume.The unit of a detection volume, a contact 56, a soldered connection 69,a readout contact 57 and a pixel electronics 67 connected to the readoutcontact 57 forms a pixel or sub-pixel. The readout and/or evaluationunit 59 is connected on the underside to a further substrate 61, forexample a ceramic substructure or a carrier plate. The readout and/orevaluation unit 59 is connected via TSV-connections 63 running throughthe further substrate 61 to a peripheral electronics 65.

FIG. 8 shows, by way of example, an embodiment of the computed tomograph31 according to the invention, with a detector device 29. The detectordevice 29 comprises the X-ray detector 1 according to the invention. Thedetector device 29 can comprise a plurality of detector modules 51 whichhave at least one X-ray detector 1. The detector modules 51 preferablycomprise a plurality of X-ray detectors 1 in a two-dimensional matrix orarray. The computed tomograph 31 contains a gantry 33 with a rotor 35.The rotor 35 includes an X-ray source 37 and the detector device 29according to the invention. The patient 39 is accommodated on thepatient couch 41 and can be moved through the gantry 33 along the axisof rotation z 43. To control and calculate the sectional images, acomputation unit 45 is used. An input device 47 and an output device 49are connected to the computation unit 45.

FIG. 9 shows the method according to the invention for regulating thetemperature of a converter material 2 of an X-ray detector 1 accordingto the invention. The method comprises the following steps:determination 71 of a first temperature, comparison 73 of the firsttemperature with a predetermined second temperature value, and adjusting75 of a current passing through an electrically conductive heating layer9 to regulate the temperature of the converter material 2. In thedetermination step 71, a first temperature is defined or measured via atemperature sensor 12, for example, on the side of the readout and/orthe evaluation unit 59 or in the readout and/or the evaluation unit 59that faces the converter material. In the comparison step 72, the firsttemperature is compared with the predetermined second temperature, bymeans, for example, of a comparator 13 in the readout and/or theevaluation unit 59. The comparison of the first temperature with thesecond temperature is carried out in a comparator 13 in the readoutand/or the evaluation unit 59, for example an integrated circuit(Application Specific Integrated Circuit, ASIC). The second temperaturecan be a yardstick or a comparative value for a temperature in theconverter material 2. In the adjustment step 75, the current passingthrough the electrically conductive heating layer 9 is adjusted toregulate the temperature or regulate the temperature of the convertermaterial 2. In the event of a first temperature that is lower comparedto the second temperature, the electric current or current flow throughthe heating layer 9 is increased. In the event of a first temperaturethat is higher compared to the second temperature, the electric currentor current flow through the heating layer 9 is reduced. In the event ofa first temperature that is the same compared to the second temperature,depending on the design of the comparator 13, the electric current orcurrent flow through the heating layer 9 is increased or reduced ormaintained at a constant value. The temperature in the convertermaterial 2 is controlled, adjusted or regulated using the methodaccording to the invention.

Although the invention has been illustrated in greater detail with thepreferred embodiment, the invention is not restricted to the examplesdisclosed, and other variants can be derived therefrom by a personskilled in the art, without going beyond the scope of the invention.

The patent claims of the application are formulation proposals withoutprejudice for obtaining more extensive patent protection. The applicantreserves the right to claim even further combinations of featurespreviously disclosed only in the description and/or drawings.

References back that are used in dependent claims indicate the furtherembodiment of the subject matter of the main claim by way of thefeatures of the respective dependent claim; they should not beunderstood as dispensing with obtaining independent protection of thesubject matter for the combinations of features in the referred-backdependent claims. Furthermore, with regard to interpreting the claims,where a feature is concretized in more specific detail in a subordinateclaim, it should be assumed that such a restriction is not present inthe respective preceding claims.

Since the subject matter of the dependent claims in relation to theprior art on the priority date may form separate and independentinventions, the applicant reserves the right to make them the subjectmatter of independent claims or divisional declarations. They mayfurthermore also contain independent inventions which have aconfiguration that is independent of the subject matters of thepreceding dependent claims.

None of the elements recited in the claims are intended to be ameans-plus-function element within the meaning of 35 U.S.C. §112(f)unless an element is expressly recited using the phrase “means for” or,in the case of a method claim, using the phrases “operation for” or“step for.”

Example embodiments being thus described, it will be obvious that thesame may be varied in many ways. Such variations are not to be regardedas a departure from the spirit and scope of the present invention, andall such modifications as would be obvious to one skilled in the art areintended to be included within the scope of the following claims.

What is claimed is:
 1. A counting X-ray detector comprising: a convertermaterial to convert X-ray radiation into electric charges; and anelectrode, the electrode being electrically conductively connected tothe converter material and the electrode being designed to be at leastpartly transparent, the electrode including: an electrically conductivecontact layer, an electrically conductive first intermediate layer, anelectrically conductive high voltage layer, an second intermediatelayer, and an electrically conductive heating layer.
 2. The X-raydetector of claim 1, wherein the electrode further includes a firstcarrier protection layer arranged in the region of the high voltagelayer or a second carrier protection layer arranged in the region of theheating layer.
 3. The X-ray detector of claim 1, wherein an electriccircuit is provided to apply a current to the electrically conductiveheating layer as a function of a first temperature determined in theX-ray detector.
 4. The X-ray detector of claim 1, wherein theelectrically conductive high voltage layer or the electricallyconductive heating layer is designed as an electrically conductive mesh.5. The X-ray detector of claim 1, wherein the electrically conductivehigh voltage layer or the electrically conductive heating layer isdesigned as a TCO layer.
 6. The X-ray detector of claim 3, furthercomprising: a temperature sensor to acquire the first temperature on aside of the converter material that is opposite the electrode.
 7. TheX-ray detector of claim 6, further comprising: a comparator to comparethe first temperature with a second temperature value.
 8. The X-raydetector of claim 1, wherein the converter material comprises cadmium.9. The X-ray detector of claim 4, wherein the electrically conductivemesh comprises at least one of the following elements: copper, silver,nickel, gold.
 10. The X-ray detector of claim 9, further comprising: anillumination device to illuminate the converter material.
 11. The X-raydetector of claim 10, wherein the electrically conductive mesh isconfigured to absorb less than 30 percent of the amount of lightradiated by the illumination device onto the converter material.
 12. TheX-ray detector of claim 1, wherein the electrically conductive contactlayer comprises one of: platinum, indium, molybdenum, tungsten,ruthenium, rhodium, gold, silver or aluminum.
 13. The X-ray detector ofclaim 1, wherein the electrically conductive contact layer is designedto be at least partly transparent.
 13. The X-ray detector of claim 1,wherein the electrically conductive first intermediate layer comprises abonding agent and an electrically conductive filler element.
 14. Acounting X-ray detector comprising: a converter material to convertX-ray radiation into electric charges; and an electrode, the electrodebeing electrically conductively connected to the converter material andbeing designed to be at least partly transparent, the electrodeincluding: an electrically conductive contact layer, an electricallyconductive first intermediate layer, and an electrically conductive highvoltage layer, designed in the form of a mesh.
 15. A medical devicecomprising the counting X-ray detector of claim
 14. 16. A method forregulating temperature of a converter material of an X-ray detector,comprising: determining a first temperature; comparing the firsttemperature with a second temperature value; and adjusting a currentpassing through an electrically conductive heating layer to regulate thetemperature of the converter material.
 17. The X-ray detector of claim9, wherein the electrically conductive mesh absorbs less than 30 percentof the amount of light radiated by the illumination device onto theconverter material.
 18. The X-ray detector of claim 1, wherein theconverter material and electrode are in a stacked array.
 19. The X-raydetector of claim 1, further comprising: a temperature sensor to acquirea first temperature on a side of the converter material that is oppositethe electrode.
 20. The X-ray detector of claim 19, further comprising: acomparator to compare the first temperature with a second temperaturevalue.
 21. The X-ray detector of claim 1, further comprising: anillumination device to illuminate the converter material.
 22. The X-raydetector of claim 21, wherein the electrically conductive high voltagelayer or the electrically conductive heating layer is designed as anelectrically conductive mesh and wherein the electrically conductivemesh is configured to absorb less than 30 percent of the amount of lightradiated by the illumination device onto the converter material.
 23. TheX-ray detector of claim 12, wherein the electrically conductive contactlayer is designed to be at least partly transparent.
 24. A medicaldevice comprising the counting X-ray detector of claim
 1. 25. The methodof claim 16, wherein the X-ray detector is a counting X-ray detectorcomprising: a converter material to convert X-ray radiation intoelectric charges; and an electrode, the electrode being electricallyconductively connected to the converter material and the electrode beingdesigned to be at least partly transparent, the electrode including: anelectrically conductive contact layer, an electrically conductive firstintermediate layer, an electrically conductive high voltage layer, ansecond intermediate layer, and an electrically conductive heating layer.26. The method of claim 16, wherein the X-ray detector is a countingX-ray detector comprising: a converter material to convert X-rayradiation into electric charges; and an electrode, the electrode beingelectrically conductively connected to the converter material and beingdesigned to be at least partly transparent, the electrode including: anelectrically conductive contact layer, an electrically conductive firstintermediate layer, and an electrically conductive high voltage layer,designed in the form of a mesh.
 27. The counting X-ray detector of claim1, wherein the converter material and the electrode are arranged in astacked array.
 28. The counting X-ray detector of claim 14, wherein theconverter material and the electrode are arranged in a stacked array.29. A medical device comprising the X-ray detector of claim 14.